Nearly all parks offer Halloween events, and that includes Six Flags. While they are all known as Fright Fest, each park has its own set of haunted mazes (such as Malice in Wonderland -- nice name! -- at The Great Escape in New York), shows, scare zones, themed rides (such as backwards-facing, lights-out coaster rides), and other special touches for the season. You can get all the gory details in my rundown of the 2012 Six Flags Fright Fests.
Photo: Six Flags. Used with permission